As many of you probably know, DealExtreme has the habit of selling AA-powered gadgets with in them the cheapest, nastiest carbon-zinc AAs on the planet.
I now have about a dozen of them that don't get any use because I don't trust them to power flashlights or gadgets, but that I don't want to throw away since their voltage is quite good on the multimeter.
I went to the local €1 store today and, inbetween the various crap that's always sold in those places, I found a nice LCD alarm clock. As luck would have it, I just so happened to need one for my kitchen.
So I bought it, got it home and cracked it open. It was powered by two tiny AG10 button cells that were already exhausted (the display wasn't very easy to read). No wonder it was selling for €1.
You can probably see where this is going.
Aah, nothing like hacking the simplest things to bring a smile to my face.
On a more serious note: don't throw away the carbon-zinc cells that manufacturers and/or resellers foist on you. I've seen people take new gadgets out of the box, remove the cells, toss them straight in the trash and replace them with alkalines before even turning on the gadget for the first time.
But carbon-zinc cells they are perfect for low-power appliances, especially if said appliances are so cheap you won't care should the cells leak inside.